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Mysterious circles in the Namib Desert: review of hypotheses on their origin [An article from: Journal of Arid Environments]
Book Details
PublisherElsevier
ISBN / ASINB000RQZG1K
ISBN-13978B000RQZG19
AvailabilityAvailable for download now
MarketplaceUnited States 🇺🇸
Description
This digital document is a journal article from Journal of Arid Environments, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Circular, slightly concave depressions, devoid of vegetation and often surrounded by a fringe of tall grasses occur in a broken belt in the pro-Namib zone of the west coast of southern Africa. Several hypotheses have been proposed to explain the origin of these so-called fairy circles. The most important of these relate to areas of localized radioactivity; termite activity; or allelopathic compounds released by dead Euphorbia damarana plants. No evidence of increased radioactivity could be detected in soil samples collected from these sites. Although termites occur at these localities no evidence was found to link termite activity directly to the formation of barren patches. Bioassays conducted on soil collected from the centre of the barren patch clearly demonstrated an inhibition of plant growth, while soil collected from the edge of the barren patch had a stimulatory effect on plant growth. No indication of growth inhibition was found in soil collected beneath E. damarana plants. At this stage none of the proposed hypotheses can satisfactorily explain the origin of the fairy circles.
Description:
Circular, slightly concave depressions, devoid of vegetation and often surrounded by a fringe of tall grasses occur in a broken belt in the pro-Namib zone of the west coast of southern Africa. Several hypotheses have been proposed to explain the origin of these so-called fairy circles. The most important of these relate to areas of localized radioactivity; termite activity; or allelopathic compounds released by dead Euphorbia damarana plants. No evidence of increased radioactivity could be detected in soil samples collected from these sites. Although termites occur at these localities no evidence was found to link termite activity directly to the formation of barren patches. Bioassays conducted on soil collected from the centre of the barren patch clearly demonstrated an inhibition of plant growth, while soil collected from the edge of the barren patch had a stimulatory effect on plant growth. No indication of growth inhibition was found in soil collected beneath E. damarana plants. At this stage none of the proposed hypotheses can satisfactorily explain the origin of the fairy circles.
